Power meters are utilized by utility companies to measure customer power usage, primarily for billing purposes. Certain smart meters measure power usage over short time intervals, and can assign a time of use (or time stamp) to the power consumed over a given time interval. The time stamping can be used in tiered or dynamic pricing schedules, for example, to provide incentives for use during off-peak times, or to charge a premium for power consumption during peak hours.
Smart meters may receive periodic network clock synchronization signals to correct local clock errors. Many smart meters are equipped with a battery or a super capacitor to enable the meter's internal clock to continue running during a power loss so that when power is restored, the time of use stamps are approximately correct. However, such storage components add to the cost of the meter. After power loss and restoration, if the meter does not have a battery or super capacitor to keep the internal clock running, the meter may not be able to assign a correct time stamp to the usage data, and revenue may be lost by the utility during the time between power restoration and synchronization with the network time.